Means to indicate shorting of precipitator by collected material



July 4, 1961 H. s. LIPPINCCTT MEANS TO INDICATE SHORTING OF PRECIPITATORBY COLLECTED MATERIAL Filed Sept. 12, 1957 W T M MM M T/ 6 m H B V. i m4 7 .w E/ JM i. 3) W F United States Patent 2 990,911 MEANS T0 INDICATESHORTING 0F PRECIPI- TATOR BY COLLECTED MATERIAL Holland S. Lippincott,Riverton, NJ., assignor to Philco V Corporation, Philadelphia, Pa., acorporation of Penn sylvania 7 Filed Sept. 12, 1957, Ser. No. 683,554 2Claims. (Cl. 1837) The present invention has to do with indicatingmeans, and more particularly to means for visibly indicating theperformance of electrostatic precipitating apparatus of the type usedfor cleaning air within a habitable enclosure.

It is known that operation of electrostatic precipitating devices ischaracterized by the presence of relatively high voltages. Accordingly,and in order to ensure safe operation of air cleaning means comprisingelectrostatic precipitators of the portable type, as well as, forexample, the type utilized in combination with window mounted airconditioners, it is important to include various safety featuresdesigned to protect users of such apparatus from the aforementionedrelatively high voltages associated therewith. Further, it is to benoted that since operation of an electrostatic precipitator issubstantially noise-free, andin the absence of moving parts in suchapparatus, a user may be unable readily to determine whether or not theprecipitator is operating, or even to distinguish between faulty andnormal operation thereof; also in certain electrostatic precipitatingapparatus it is necessary that the user periodically clean or replacedust collector elements comprising electrodes of the high voltageelectrical circuitry, and it is imperative that means be provided forwarning the user of the presence of hazards, in the event ofmalfunctioning of conventional interlock means provided for deenergizingthe apparatus upon disassembly of the same.

Heretofore, no simple, reliable and positive means for indicating thecondition of operation of such equipment, in these important respects,has been available. It is, accordingly, the general object of thisinvention to provide a novel electrical circuit comprising but a singlevisible indicating means for indicating that the precipitator isoperating, that the collecting electrodes, or filters, have become dirtyand are in need of replacement, and that the electrical interlockapparatus is operating properly.

It is an additional object of the invention to provide in electrostaticprecipitating apparatus visible signaling means for indicating presenceof a shock hazard.

A still further object is to provide signaling means of the foregoingtype which has a useful life of long duration and requires a minimum ofcare on the part of the user.

In the achievement of the foregoing and other objects and advantages, apreferred embodiment of the present invention comprises, in combinationwith an electrostatic precipitator, signaling or indicating meansincluding a glow-discharge lamp disposed in novel and suitableelectrical circuitry with an electrode of the precipitator. Theinvention, in an important aspect thereof, contemplates locating thelamp in series electrical circuitry with the discharge and collectingelectrodes of so-called single stage precipitator apparatus, the latterbeing characterized in that the aforesaid electrodes cooperate toprovide a combined ionizing and collecting field.

The novel features of the invention, and the manner in which theforegoing and other objects and advantages are best achieved will beapparent from the following description taken in view of theaccompanying drawing, in which:

FIGURE 1 is a perspective showing of a window mounted room airconditioner made in accordance with a preferred embodiment of theinvention;

FIGURE 2 is a view similar to FIGURE 1, but showing a portion of thehousing structure removed;

' FIGURE 3 is a somewhat enlarged fragmentary sectional view of theapparatus shown in FIGURE 2;

FIGURE 4 is a further enlarged fragmentary view of apparatus shown inFIGURE 3;

FIGURE 5 is an enlarged fragmentary view, in elevation, of apparatusshown in FIGURE 2; and

FIGURE 6 is a schematic showing of the electrical circuitry ofprecipitating apparatus embodying the invention.

Prior to a detailed description of the novel apparatus in light of theaccompanying drawing, it is pointed out that for purposes ofillustration the present invention is embodied in combined filtering andrefrigerating apparatus of the type dis-closed and claimed in thecopending application of Robert G. Kurtz, Serial No. 647,540, filedMarch 21, 1957, now US. Patent 2,933,151, and assigned to the assigneeof the present invention.

Now making more detailed reference to the drawing, and particularly toFIGURE 1, the-re is shown a conventional window mounted air conditioner10 including a cabinet 11 and a conventional decorative panel 12.Disposed in the decorative panel are the inlet and outlet air grilles 13and 14, respectively, each being in air flow communication with theusual refrigerating and air moving means (not shown) housed within theair conditioner cabinet.

Shown in FIGURE 2 is air conditioner 10 with the decorative panel 12removed to expose electrostatic filtering and ionizing means 15 in novelcombination with indicating means, designated generally by referencenumerals 15a, with which this invention is concerned. In accordance withthe embodiment illustrated, the construction and arrangement of thefilter 15 is such that it is disposed intermediate the inlet grille 13and the inlet air duct 17 of the air conditioner. There is also shown inFIGURE 2 a suitable electrical component structure or pack 16, 16a,including cycle controls, indicated at 18 and 18a as well as ionizingvoltage supply means 19. Additionally, there is provided suitableinterlock switch means 1812, which in the embodiment illustratedcomprises a push button switch operably engageable with decorative panel12, selectively to deenergize or energize voltage supply 19, inresponse, respectively, to removal or installation of the latter.Additionally, there is provided a suitable manually operable switch forselectively deenergizing and energizing voltage supply 19. Access to theabove mentioned switch 18c and controls 18, 18a, as well as indicatingmeans 15a, is accommodated by a suitably hinged cover 12a provided inthe panel 12.

Now referring again to FIGURE 2, there is shown filtering and ionizingmeans 15, including a sleeve-like housing 20 provided with a suitabledetachable cover 20a. As seen in FIGURE 3, cover Zlla has been removedthereby providing access to the filter elements to be hereinafter morefully described. Attachment of filtering means to the air conditionermay be made in any suitable manner, and it is seen in FIGURE 3 that thepreferred embodiment contemplates the simple expedient of attachinghousing 20 by screws 22 passing through flanges 21 thereof and into theair conditioning cabinet 11. Additionally seen in FIGURE 3 are upstreamand downstream impingement type filters-or collector electrodes 23 and23a, preferably of metal construction and including coatings of viscousmaterial (not shown). The filter illustrated comprises a filter medium24 of several layers of expanded aluminum sheet supported Within analuminum frame 25. Serving further to rigidity the frame 25 are diagonalcross members 26 which are attached at the corners of the frame by knownsuitable means.

Retaining means for filters 23 and 23a include guide channels 27comprising flange portions 28 and 28a of housing 20, and edges 29 of aninsulating frame 30 (to be hereinafter more fully described), saidchannel being adapted slidably to receive the filters for removal andinsertion thereof. Disposed in one of the aforementioned channels 27,preferably although not necessarily the upstream channel, is aninsulating member 27a comprising an L-shaped sheet of suitable materialwhich serves elec trically to insulate frame 25 of metal filterelectrode 23 from the housing 20 for reasons to be hereinafter morefully explained.

Referring further to FIGURE 3 there is seen an electrode 32 supported ina serpentine manner by frame 30 which is electrically non-conductiveinvertically extending parallelly disposed spans lying substantially in aplane extending transverse the direction of air flow.

Immediately downstream of the second metal filter 23a is a charcoalfilter 35 adapted for slidable insertion into or removal from channels36, much in the manner of filters 23 and 23a. Insertion and removal ofthe foregoing elements is accomplished through the mentioned top accessopening provided in housing 20, as best seen in FIGURE 3, and with thecover 20a removed. Additional structure includes wire screens 37 aflixedto the inner faces of the filters 23 and 23a. These wire screens insureproper spacing of the filter media 24 from the ionizing wire 32,inasmuch as metallic filter media of the type illustrated is sometimesflexible and movement thereof may upset the substantially criticalspacing between the ionizing wire and the collector electrode.

A tensioning means 40 comprising spring 41 is aifixed at one end tosuitably formed portion 42 of the web 38 and at the other end toclamping means 43 aflixed to wire 32. Enclosing the tensioning means 40is a sleeve-like member 44 of electrically insulating material.Tensioning means 40 will advantageously compensate for variations in thelength of wire 32 and therefore aid in maintaining proper spacing of thewire from the collector electrodes 23 and 23a by preventing unduesagging of the wire.

Suitable electrical terminal means (not shown) is associated with theionizing wire to accommodate energization of the same by wire lead 46(FIG. 6) to be hereinafter described.

In the channel member 27 adapted to receive the downstream collectingelectrode 23a there is disposed a leaf spring 31a adapted resiliently tobear against the inserted electrode to retain the same and enhanceelectrical contact of the latter to grounded housing 20. There isfurther provided in the channel member 27, adapted to receive upstreamfilter 23, a leaf spring 31 adapted to bear against insulating member27a which is thereby urged against an inserted filter 23, to retain thesame.

In particular accordance with one aspect of the present invention, andas best seen in FIGURE 4, an aperture 20b is provided in housing 20,said aperture accommodating passage of wire lead 59a. Wire lead 59a iselectrically connected to leaf spring contact 31b by means of eyelet310, the latter serving also to mount contact 31b upon insulating member27a. Thus it is seen that filter electrode 23 is electrically insulatedfrom the grounded housing 20, and the sole electrical contact to thefilter 23 is made through the above described contact 31b.

Now referring to FIGURE there is seen in detail the indicating means 15ashown in FIGURE 2, said means comprising a capacitor 15b and a lamp 150of the type commonly known as a glow-discharge lamp. There is of courseincluded known suitable bracket means B associated with structure 16afor supporting the capacitor 15b as well as known snap-action means Sfor holding the base portion of lamp in a suitable aperture provided inthe aforementioned structure 16a. There is also provided associatedelectrical circuitry for incorporating the indicating means into theelectrostatic filtering circuit, said circuitry including wire lead 59a,terminal means T for grounding leads 59b and 590, as well as connector Dfor joining leads 59d and 5% to 59a.

Now referring to FIGURE 6 of the drawing there is seen a schematicdiagram of suitable electrical circuitry for producing the desiredcombined ionizing and collecting electrostatic field, in novelcombination with the indicating circuit with which the present inventionis concerned.

Transformer 55, the primary winding of which may be supplied, throughinterlock switch 18b and manual switch 18c, with electrical power from asuitable source, supplies a voltage, for example about 6000 volts, to ahalf wave rectifier tube 56, the same D.-C. voltage being impressedacross ionizing electrode 32 and filter electrodes 23 and 23a. Thisvoltage is maintained substantially constant by resistor 57 and coronadischarge tubes 58, and condenser 60 provides means for maintaining peakvoltage supplied by the rectifier tube 56. A resistor 61 is alsoprovided as shown, to control the current through the electrodes 32 and23, preferably limiting the current to a value of about 10 microamperes.

In particular accordance with the present invention, lead 59a extendingfrom the spring terminal 31b contacting the electrodes 23 and 23a isconnected to ground 59 through the glow-discharge lamp 150 and thecapacitor 1511, the latter elements being connected in parallel asshown. Lamp 150 comprises a suitably encapsulated neon lamp of the typeknown commercially as Ne2, & watt, and capacitor 15b comprises acylindrically formed .067 fd. condenser of known type.

Thus, the novel indicating means is disposed in series with a collectingelectrode of the air cleaning and filtering apparatus. Disposition ofthe indicating means in the circuit is such that functioning of the highvoltage elements, as well as the apparatus preceding the same will beindicated.

In preferred operation of such a combined filter and ion generator anegative potential is applied to the ionizing wire 32 whereuponelectrostatic fields are set up between the ionizing vvire and theupstream and downstream filters, or electrodes, at least the formerbeing grounded through the novel indicating apparatus 15a. Accordingly,a charge builds up on the upstream filter electrode 23, as well as onthe capacitor. When the firing potential of the neon lamp 150 isreached, the builtup charge discharges to ground through the lamp,accompanied by glow of the latter. The aforementioned cycle isrepetitive in nature, and the frequency of its occurrence will depend,for example, upon the value of the corona current existing at theionizing wires. Such current may be a function, for example, of thepresence of an excessive accumulation of particulate matter upon theelectrode 23, this matter tending to bridge the insulating members 27a,30 and housing 20, thereby electrically to ground the said electrode;particulate accumulation is therefore reflected in that a longer periodof time is required to build up to the firing potential of the neon lamp15c, to light the same. It is seen therefore that because the lamp is inseries with the high voltage elements, excessive particulateaccumulation is readily indicated. Thus, progressive fouling of filter23 will be indicated by a diminishing frequency of light pulsation orflicker. In the event of component malfunctioning, the nature of theelectrical circuitry is such that the lamp will of course cease to fire,thereby indicating a failure in the system, inasmuch as the necessarylamp firing potential will not be attainable. Finally safety of a userof the apparatus is ensured by visual indication of the presence of ashock hazard in the event the interlock feature should fail todeenergize the high voltage .ija

circuit upon removal of the panel 12. Thus, as will now be appreciated,complete operation of the air cleaner is indicated, and failure of anyphase of its operation will be indicated by the device hereinbeforedescribed.

Although, in the illustrated embodiment of the present invention, thenovel indicating means has been disposed in series circuit with theupstream collector electrode 23, it is to be understood that thedownstream collector electrode 231! may be disposed in like circuitrywith the indicating means, either singly or in tandem with the upstreamelectrode 26.

While this description and the accompanying drawing are illustrative ofa preferred embodiment of the invention, it will be recognized thatchanges and modifications may be made in the described apparatus,without departing from the scope of the appended claims. For example,there may be provided unitary indicating means 15a comprising theessential elements illustrated in FIG- URE 5, whereby the means 15aserves as a portable test instrument to use with precipitating devicesnot thus equipped. To this end, element 16w may comprise suitableinsulating frame structure, and terminal T and lead 590! could bemodified by affixing thereto leads provided with suitable known clipmeans for attaching to appropriate electrical components of aprecipitator.

I claim:

1. In single stage electrostatic precipitator apparatus, a dischargingelectrode and a collector electrode consisting of an electricallyconductive filter screen, means for applying a high D.-C. potentialbetween said electrodes to create a combined particle ionizing andcollecting field therebetween, and visibly pulsating indicator meansoperative over a range of pulse frequencies and including means forchanging said frequencies in response to changes in the amount ofparticulate collection by said filter screen.

2. Precipitator apparatus in accordance with claim 1, wherein saidindicator means comprises a capacitor and a glow discharge lamp arrangedin parallel circuit and each disposed in series electrical circuitrywith said filter screen and said means for applying a potential.

References Cited in the file of this patent UNITED STATES PATENTS2,129,783 Penney Sept. 13, 1938 2,189,614 Penney Feb. 6, 1940 2,579,441Palmer Dec. 18, 1951 2,738,443 Danziger Mar. 13, 1956 2,791,725 WilliamsMay 7, 1957 2,798,572 Fields July 9, 1957 OTHER REFERENCES Articletitled Novel Test Meter, in vol. 47, issue 4, page 42 of April 1952issue of Radio and Television News.

